1. Field of the Invention
The present invention relates to a technology to be adopted when implementing autofocus control in a microscope.
2. Description of the Related Art
Autofocus systems adopted in conjunction with microscopes in the known art include image contrast type autofocus systems. When observing a biological specimen in a fluid under fluorescent light with an optical microscope (a biological microscope), such an autofocus system detects the contrast of the fluorescent image and executes a focal adjustment in conformance to the position at which the maximum contrast is achieved.
However, there is a problem with image contrast type autofocus systems in that the contrast of the image of a specimen with a pale color cannot be extracted quickly and thus it takes a considerable length of time to execute the focal adjustment. Since fluorescent light fades quickly, when a specimen is observed under fluorescent light with a biological microscope the image may even disappear during the focusing process on the fluorescent image.